The Alien Megastructure Star May Have Eaten A Planet

Remember the alien megastructure star? Yes, it was that strange star that was experiencing large dips in light, leading to the suggestion – however unlikely – that aliens might have built a giant structure around the star.

Of course, we’re pretty sure that’s not the case. But since the star called KIC 8462852 – also known as Boyajian's Star or Tabby’s Star – jumped onto the scene in 2015, plenty of other theories have been put forward to explain the dips in light, from comets to magnetic field “avalanches”, with little accord. Now, a new study from Columbia University says the strange signal may be the result of the star eating one or more planets.

The star was seen dipping in light by up to 22 percent by the Kepler telescope over the last few years. But records show it also dipped by 14 percent from 1890 to 1989. The comet theory was contentious because it was difficult to see how there would be enough debris to cause these large dips. So maybe, instead, a planet is the cause.

“We propose that the secular dimming behavior is the result of the inspiral of a planetary body or bodies into KIC 8462852,” the researchers write in their paper, available on arXiv. They add that it may have occurred up to 10,000 years ago.

This means that the dips in light may be the result of debris left behind by a planet being eaten. And, what's more, some of the dips may not be caused by something obscuring our view, but rather a consequence of the event; the consumed planet could have caused the star to increase in brightness, and it is only now returning to its regular state.

The researchers don’t necessarily rule out other theories, though. They say such an event – there could have been several – may have put comet or planet debris into a highly eccentric orbit around the star, playing some part in the dips in light.

So, it might not be aliens, but the alternatives being touted for this star are still exciting. If this particular theory holds true, it may force a rethink on how stars and their planets interact.

“We estimated that if Tabby’s Star were representative, something like 10 Jupiters would have to fall into a typical star over its lifetime, or maybe even more,” lead author Brian Metzger told New Scientist.